Glossary
Fake
In one line: Making the defense believe you are hitting one site, then going to the other.
What it means
A fake is a feint: you make noise, throw utility and show a few players on one site so the defense rotates there. Then the team (or most of it) hits another site, which now has fewer defenders.
A fake has a cost: utility, time, sometimes a player. It works if it is convincing (enough noise and utility to look real) and if the team knows when to stop and switch. Against a defense that never rotates, a fake achieves nothing.
An example
Two players throw smokes and a flash into A main and make noise. The defense sends two players from B towards A. Meanwhile three of you hit B, where only one defender is left.